Combined foot brake and accelerator control for motor vehicles



Feu/2,1937., f, NA. D. MCLEAN y 2,069,618

COMBINED FOOT'BRAKE AND yAcJCELEMTOR CONTROL FOR MOTOR VEHICLES FiledAug. 19, 1935 W Y Y Ill/1111111 'lz/111,111

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v Y @I James Algernon DIEA'VICIISEH Mclean INVENTO@ Patented Feb. 2,1937 UNITED STATES COMBINED FOOT BRAKE AND VACCELER- ATOR CONTROL FORMOTOR VEHICLES James Algernon Dietrichsen McLean, Hampstead Gardens,Australia Application August 19, 1935, Serial No. 36,755 In AustraliaMay 3, 1935 4 Claims.

My invention relates to a combined foot brake and accelerator controlfor motor vehicles, the object of the same being to provide meanswhereby an accelerator and brake lever and connec- 5 tions can beoperated from an adjustable pedal 'either for the purposes ofacceleration or in the alternative to enable the brake mechanism to beapplied without removing the operators foot from the pedal.

In operative brake mechanism hitherto in general use foot pressureapplied to a brake pedal has resulted in transmitting the brake effectto the wheels of the vehicle with which such brake mechanism isspecication the means provided for operating the brake is such that thedepression of the brake pedal instead of applying the brake, as hashitherto been the usual custom, not only releases the brake instead ofputting it on, but in addition to such action compresses a spring whichis thus made ready to apply the brake when required upon the release ofthe foot pedal pressure, the fuel supply remaining unaffected during thewhole of the movement required for applying the brake, and converselyduring the whole of the movement required for regulating the fuelsupply, the brake connections are not affected.

For the purpose of my invention I provide a strong horizontal bar,hereinafter referred to as box or casing which is secured to the frameof a chassis and upon which I mount an arm or lever in the upper end ofwhich is a screw threaded socket or hole in which the screw threadedyend of a foot pedal shank is accommodated.

Between the shaft and the pedal shank I pivot a tube into which isinserted a rod which controls the throttle of the engine to which mydevice is applied, the device being also applicable for controlling thefuel supply when used with Diesel engines.

The brake mechanism is adapted to be operated by the pedal and lever bymeans of a cam, or its mechanical equivalent, formed on the pedal shaftwhich operates a piston having a spring'return with which a brakeoperating rod is associated, the general arrangement being such that thefoot pedal functions for opening or closing a throttle; applying thebrake by releasing the pedal and accelerating the speed byfoot-pressure, means being provided for adjusting the spring to thetension required to operate the brake or brake mechanism as the case maybe.

But in order that my invention may be more clearly understood I will nowdescribe the same associated. In the following the pedal shaft,accommodated within a metal by aid of the accompanying illustrativedrawing wherein:-

Fig. 1 is a sectional side elevation of my device with foot leverelevated.

Fig. 2 is a sectional elevation of the same device with the leverpartlydepressed.

Fig. 3 is a plan of Fig. l.

Fig. 4 is a modification of the structure shown in the preceding iiguresin which a portion of the cam is extended and the pedal is in itsuppermost position.

Fig. 5 is a plan-of Fig. 4;

Fig. 6 illustrates by diagram certainfeatures of cam construction.

In each of the illustrations similar letters of reference are used todenote similar or corresponding parts wherever they occur.

In the drawing a is a gearbox or casing which is securely fastened to achassis and is constructed with bearings for the accommodation andsupport of a transverse pedal bar b, to which istattached a main leverd. In the bottom of the gear box I provide a screw threaded stud c whichis adapted to actas an adjusting device or stop to serve the purpose oflimiting the upward moved plate is indicated at e. -The length of thispedal support may be adjusted by means of itsy screw threaded portionwhich passes through the lever and is secured by aV lock nut e2. Near tothe upper end of the main lever I rotatably mount a throttleoperating'device consisting of a sleeve portion j and a sliding rod f.

In addition to the main lever d I mount upon the shaft b a cam g, themovement of which is controlled by the movement of the lever d. This camis designed and arranged to operate the brake connections hereinafterdescribed, and the traverse of its downward rotary movement is limitedby the stud c. In constructing the camV If formA part of its operatingsurface to the shape of a curve consisting of two arcs gf and g2 oiconcentric circles (Fig. 6) joined by a straight or Vcurved line g3, thedifference ofthe radiiof the two arcs beingA equivalentto thev distanceof the travel of an associated brake-operating piston and rodhereinafter described.

Holes g4 in the cam are so placed that when a locking pin is inserted inthe `vlower hole the foot brake is held olf for convenience whilstadjusting brake shoes or brake bands, or when moving the vehiclewithoutvthe aid of its engine.

i Y When the locking pin is inserted in the upper hole the brake is heldin the full on Vposition as a preventative against theft. These holesare sltuated Vat'even radial positions from the centre of the levershaftas `indicated in Fig. 6, and travel by radial movement to'positionsin alignment with a locking pin o as will be understood upon referenceto Figs. 3 and 5.

Rearward of the gear box or casing I secure a tubular construction 7' inwhich I support a coil spring [c and through the centre of the tubularconstruction I support a horizontal rod lupon the forward end of which Ifasten a piston l" in which a guide pin Z2 (Figs. 1, 2 and 3) isfastened and operates within a corresponding slot inthe tubularconstruction to prevent the rotation of the piston according tousualpractice. Y

The end of the tubular construction j s closed with a screw threaded:plug m which can be rotated vin either direction so as to increase ordecrease thetension of the spring.V The horij zontal rod Z isV eitherdirectly or indirectly conand 5) which upon being fitted with a key canclutch or electric switch as the case may be.

Where brakes depend on foot pressure entirely the spring must besufliciently powerful to pull the brake on hard enough to lock thewheels.

Within the casing and preferably integral with it vI provide a boss a.for a cylinder lock (Figs. 3

operate a locking pin o andenable it to be directed into eitherV of theholes'gfl in the cam plate so as to retain the lever mechanism inthepreferred position. I am aware `that one-position locks of a somewhatsimilar nature have Y hitherto been used and for a single purpose.

In Figs. 4 and 5 I have shown a slight Vmodication Vof my device whereinthe piston l' in-A stead of impinging directlyupon the cam g is operatedby a short connecting link prwhich responds to the rotary movement ofthe pedal shaft -and causes Ythe brake` operating rod to traversebackwards or forwadsrin obedience to the movement of the main lever andpedal. This modification is more particularly applicable tovvehicleswherein `brake mechanism is actually applied byV some'external forcedriversV foot. Y

In Figs 1 and 2 I have indicated an external return spring t one end ofwhich is fastened to the casing a, the opposite end being secured to themain lever d so that when pressure is removed from the lever the leverwill make a rearward movement farther than that which is reand onlyregulated by Ythe Vquired to close the throttle, thereby allowing thepiston l tof slide off the higher part `of thecarn, whereupon the springlc will push the piston for- Y Y Vfward and thereby move the rod Zforward and operate the foot brake to thedesired extent.

In the 'case of a vehicle with foot brakes wherey the necessary pressurewould be supplied by the drivers foot, the rod l is attached at its rearend to the same part of the foot brake mechanism as the rod from anordinary foot brake pedal' Vwould be attached toit.

In the case of a vehicle fitted with hydraulic brakes the rod Z would beconnected Yat right angles to end of a compensating bar pivoted at q'near its centre v(Fig. 2 extended), to theother end of which a rod 1'would be pivoted at right angles projecting in the opposite direction tol,

and so connected with av master cylinder srthat the forward movement ofthe rod Zwould cause the rod r to force thepiston of such mastercylinder intel-its cylinder.

In the case of a vehicle fitted with foot brakes operated bycompressedv` air, vacuum, electric or other so-called servo-mechanismthe rod l would be attached to a controlling valve, switch,

clutch or other controlling: device of such servomechanism in suchVaV-manner that the forward movement of the rod would applythe footbrake.

The operation ofY the mechanism of my invention, briefly stated, is asfollowsz 'Y When the vehicle is stationary the pedal is i the uppermostposition with the cam against the stop. Y When the vehicle is to bedriven-the pedal t is depressed about three-quarters of its movetmentuntil the pistonslides on toi the bottom of the arc of greater radiusofthe cam. The piston is thus forced back against the spring and the o Yfoot brake released. y

By this timethe rod, connected with the throttle or fuel control, willhave reached the closed end of the sleeve, andthe further downwardmovement of thepedal opens the throttle or increases the fuel supplyupto its full extent. During this further movement,k the piston slideson inthe arc of greater radius of the cam andthe brake rod thus remainsunmoved.- 'g v y In the modification shown in Figs. 4 and 5 the camextension' and the link p move slightly Von either side of astraight'line joining the centre of the pedal shaft and piston duringthe'portion of the pedal movement devoted to accelerating the engine,and thus move the brake rod only brake to be applied;

This modification is more rsuitable in brake mechanism operated byexternal forceand only regulated by the drivers foot, when the 'springVneed be only powerful enough to actuate the controlling valve switch orother equivalent fdevice.v

From the foregoing specification it will'thus be vseen that the act ofdepressing the pedal e' instead of applying the brakeas has `hithertobeen the usual custom, releases the brake and at to a very small extent,not sufficient to allow the Y the same time compresses the spring k,which is j thus made ready to applythe brake when required upon therelease of the foot pedal pressure, the

fuel supply not being affected duringfythe whole,r

of the movement required for applying the'brake while during the wholeof the movement required tions are not affected.

What I claim isz- Y 1. In acombined foot brake and accelerator forregulating the fuel supply the brake connec-A erable from a shaft and alever rigidlyconnected `control for motor vehices, a tubular structurewhich is firmly fastened near one end of a brake:

and accelerator control'box, a sliding piston opto said shaft, saidpiston kbeing accommodatedV K within the tubular structure and havinga=rod .attachedY thereto which' is connected wth'brake mechanism, acompression spring contained Within the tubular structure in Which oneend of said spring abuts the piston, the opposite end of the springbeing adapted to rest against a screw threaded adjusting plug.

2. In a combined foot brake and accelerator control for motor vehicles,a lever of cam-like construction which rotates in unison with a shaftand is actuated by the brake lever, a link one end of which' is attachedto a brake actuating piston the other end being adapted to move throughan arc of a circle whereby the piston is caused to advance or retirewithin its cylinder thereby operating brake mechanism.

3. In a combined foot brake and accelerator control for motor Vehicleswherein a lever of cam like construction is secured to a shaft andadapted to be operated by a foot lever is used, two

holes of equal size formed within the cam and of equal radial distancefrom the centre of the cam shaft, said holes being spaced for theaccommoda-V tion of a locking pin which is adapted to maintain the levermechanism in either of two positions in relation to the brake mechanismand a locking pin slidably supported within a portion of the casing andadapted to engage in either of the aforesaid holes. Y

4. In a combined foot brake and accelerator control for motor vehicles,a connecting link pivotally mounted at one end upon a lever'of cam likeconstruction attached to a transverse pedal shaft, the opposite endbeing attached to and adapted to operate a sliding brake rod and piston.

JAMES ALGERNON DIETRICI-ISEN MCLEAN.

